Abstract: The analysis and research on the space between nuclear island buildings in nuclear power plants are relatively few at preseat.The analysis and research of nuclear island plant spacing of nuclear power plant has a very important impact on the general layout of nuclear power plant, which can not only save the plant area, but also shorten the length of outdoor pipelines and corridors, especially for the site with limited bedrock surface, which has a very important economic significance. This paper takes one nuclear power project as an example, adopting the method of integrating theory with practice and analyzing the plant spacing of nuclear island in nuclear power plant, and obtaining the value of nuclear island plant spacing and precautions, so as to provide a certain optimization basis for optimizing the general layout of nuclear power plant.